Blastoid (ポンター,Pontā?, lit. "Ponter") is a Badnik created by Dr. Robotnik. It appears at Hydrocity Zone in Sonic the Hedgehog 3. It is a small blue and yellow colored cannon with small eyes which fires energy projectiles. Blastoid isn't much of a threat to the player, but it can catch them off guard.
When approached, Blastoid will shoot three energy projectiles to the player's direction at a 45 degree angle. Blastoid has been deployed in areas where it can be hard to avoid, although it lacks the ability to aim. The energy projectiles it fires can be deflected by any shield available in the game; the Water Shield, which is common in the Hydrocity Zone, is the best one to use, as almost all Blastoids are located underwater.
The Pokémon franchise has a Pokémon named Blastoise, which is similar to Blastoid. In fact, both are blue, have a large cannon and have some-sort of water-based features.
One of the enemies in Sonic Advance 3, the Clam, has an identical attack pattern to the Blastoid.